There is a guy on mbworld.org that has perhaps the best CLK430 he has extensive mods, pushing 400hp at the wheels, I am quite sure he would give a Kleemann CLK55 a run for its money.
Check his car out here.
http://forums.mbworld.org/forums/showthread.php?s=&threadid=6197
Now dont go living Mercedesshop for MBworld, lol
Subman